Connector assembly for a drilling apparatus

ABSTRACT

A connector assembly ( 10 ) for use with a drilling apparatus, comprises an input connector unit ( 12 ) which is connectable to a drill motor, an output connector unit ( 14 ) which is connectable to a drill pipe string and a number of shock absorption elements ( 16 ). The input and output connector units ( 14 ), ( 16 ) include top and bottom carrier plates ( 26 ) and ( 31 ), respectively. The shock absorption elements ( 16 ) are arranged adjacent one another between the carrier plates providing for absorption of both axial and rotational shock forces transmitted between the drill motor and the drill string. The connector assembly includes elongate link elements ( 70 ) extending between the top and bottom carrier plates which prevent separation of the carrier plates beyond a predetermined separation spacing limit.

FIELD OF INVENTION

This invention relates to a connector assembly for use with a drilling apparatus.

BACKGROUND TO INVENTION

A connector assembly as herein envisaged is disposed between the output of the drill motor of a drilling apparatus, as used for drilling holes in open cast mines, and the like, and a drill pipe of the apparatus having a drill bit at a lower end thereof. The drill pipe itself is made up of a string of drill pipe segments including a drilling segment incorporating the drill bit and extension segments that are located, one after another, in line with the drilling segment, to provide for a hole to be drilled to a required depth. The drill pipe segments and the output of the drill motor conventionally define complementary thread formations whereby they are releasably connected in line with one another, the segments generally defining a passage therethrough through which a cooling fluid under pressure, such as compressed air or liquid, can be conveyed to the working end of the drill pipe, for cooling purposes during drilling and/or for displacing dust particles formed as a result of drilling, commonly referred to as chippings, from a hole being drilled. The cooling fluid exits via holes in the drill bit and travels up an annular space defined between the drill pipe and the wall of a hole being drilled by the drill bit. In this manner, chippings are conveyed by the cooling fluid upwardly and out of the hole.

It is known in relation to the use of drilling apparatus of the above type that as drilling progresses, further extension segments are connected, one after another, in line with the drill pipe, whereas the withdrawal of the drill pipe from a hole drilled requires the reverse to occur, i.e. extension segments are removed, one after another, from the drill pipe. The drilling of holes, therefore, is a stop/start operation and for this reason and also generally due to the nature of drilling holes in mining environments, rotational and axial shocks are transmitted through a drill pipe to the drill motor of the drilling apparatus. As such, and in order to avoid damage to the drill motor as a result of, in particular, rotational shocks, a connector assembly, that serves as a shock absorbing assembly, acts between the drill pipe and the output of the drill motor, the present invention relating specifically to such a connector assembly.

A known connector assembly provided for the above purpose is disclosed in the present applicant's South African Patent 2006/08497 which includes an input shaft segment connectable to the output of a drill motor of a drilling apparatus, a single drive body connected to the input shaft segment, an output shaft segment connectable to a drill pipe segment of a drill pipe, a single driven body connected to the output shaft segment, and a housing structure within which the drive body and the driven body are housed. A deformable shock absorbing filler material is introduced into the housing structure in a flowable form and allowed to set and cure so as to act between the drive body and the driven body in order to absorb potential rotational and axial shocks transmitted between them during a drilling operation.

The input shaft segment is welded to an upper carrier plate to which the drive body is bolted, while the output shaft segment is welded to a lower carrier plate to which the driven body is bolted. A cylindrical casing is connected to the lower carrier plate and extends upwardly to the upper carrier plate, the carrier plates and the casing together constituting the housing structure.

A problem encountered with the applicant's connector assembly disclosed in ZA Patent 2006/08497 is that the entire connector assembly needed to be disconnected and removed from the drilling apparatus in order to repair to any of the components thereof or for maintenance work to be carried out on any components thereof. Furthermore, due to the integrated design of the connector assembly, any major damage to a component thereof often resulted in the entire connector assembly being rendered irreparable and thus discarded.

Another known connector assembly which at least partially addresses the abovementioned problem encountered with the applicant's connector assembly disclosed in South African Patent 2006/08497, is disclosed in the applicant's South African Patent 2013/08145. The connector assembly disclosed in ZA Patent 2013/08145, includes an input connector unit and an output connector unit connectable to a drill motor and a drill pipe segment of a drill pipe, respectively, a housing structure including top and bottom cover plates and defining an internal chamber, a number of drive bodies welded to the top cover plate and a number of driven bodies welded to the bottom cover plate, the drive and driven bodies being housed with the internal chamber. The input and output connector units are releasably mounted to the top and bottom cover plates of the housing thereby to permit disassembly of the input and output connector units. The drive and driven bodies are of fabricated steel and a resiliently deformable shock absorbing body is formed within the internal chamber of the housing so as to surround the drive and driven bodies, by filling the chamber with a shock absorbing material while in a flowable form and allowing the material to set and cure within the internal chamber.

Although the connector assembly disclosed in South African Patent 2013/08145 addressed some of the shortcomings of the connector assembly disclosed in South African Patent 2006/08497, the applicant found that in order to repair one of the drive or driven bodies which are subjected to significant wear and tear, in use, the entire connector assembly needed to be disconnected and the top or bottom cover plate removed together with the connector unit associated therewith, for repair or replacement. A single damaged drive or driven body cover plate often resulted in the entire top drive body unit or the entire bottom cover plate/drive body unit being replaced. The removal and replacement of the top cover plate unit and of the bottom cover plate unit was also problematic due to the space surrounding these units within the internal chamber of the housing being filled with the shock absorbing body. In practice, the housing and the cover plate units would need to be stripped of the shock absorbing body material prior to repair or replacement of a cover plate unit.

It is an object of the present invention to provide a connector assembly which ameliorates the abovementioned problems experienced with the applicant's previous connector assemblies.

SUMMARY OF INVENTION

According to the invention there is provided a connector assembly for use with a drilling apparatus, the connector assembly including:

an input connector unit including a top carrier plate and an input shaft which is connected to the top carrier plate, the input shaft having an open upper end and an open lower end and an internal passage extending between the upper and lower ends, the upper end having a connector formation which is connectable to a power output of a drill motor of the drilling apparatus;

an output connector unit including a bottom carrier plate and an output shaft which is connected to the bottom carrier plate, the output shaft having an open upper end and an open lower end and an internal passage extending between the upper and lower ends, the lower end having a connector formation which is connectable to a drill pipe segment of a drill pipe; and

at least one resiliently deformable shock absorption element which is mounted between the top and bottom carrier plates so as to absorb axial shocks transmitted between the drill motor and the drill pipe,

the input and output shafts defining a common longitudinal axis, with the internal passages of the input and output shafts being in flow communication with one another and an internal passage of the drill pipe.

The top carrier plate may define a central aperture within which the input shaft is received.

The bottom carrier plate may define a central aperture within which the output shaft is received.

The lower end region of the input shaft of the input connector unit may project beyond an underside of the top carrier plate.

An upper end region of the output shaft of the output connector unit may project beyond an upper side of the bottom carrier plate.

The connector assembly may include a sealing member located between the lower end of the input shaft and the upper end of the output shaft, the sealing member defining a central passage which is aligned with the internal passages of the input and output shaft thereby to form a sealed common central internal passage extending through the connector assembly.

The connector assembly may include a number of shock absorption elements which are arranged adjacent one another between the top and bottom carrier plates.

Each shock absorption element may comprise a shock absorption body having a central core member of a resiliently deformable shock absorption material, an upper rigid plate and a lower rigid plate fixedly located at upper and lower ends, respectively, of the core member.

The shock absorption element may include at least two upper locating pins which extend upwardly from an upper side of the upper rigid plate and at least two lower locating pins which extend downwardly from a lower side of the lower rigid plate, the locating pins extending parallel to the longitudinal axis of the connector assembly.

The central core member of each shock absorption element may be of rubber, while the upper and lower rigid plates of each shock absorption element may be of steel.

The top and bottom carrier plates may define locating holes within which the upper and lower locating pins, respectively, are slidably received.

The upper and lower locating pins may have stop elements near free ends thereof at external sides of the top and bottom carrier plates, the stop elements resisting separation of the top and bottom carrier plates beyond a predetermined separation spacing limit.

The connector may include a number of elongate link elements which extend between and which are connected near opposite ends thereof to the top and bottom carrier plates, respectively. More specifically, the top and bottom carrier plates have mounting formations for mounting the link elements, disposed near peripheral edges of the carrier plates, the link elements extending between aligned mounting formations of the top and bottom carrier plates, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of a connector assembly for use with a drilling apparatus, in accordance with the invention are described hereinafter by way of a non-limiting example of the invention, with reference to and as illustrated in the accompanying diagrammatic drawings. In the drawings:

FIG. 1 shows a three dimensional view of a connector assembly in accordance with the invention;

FIG. 2 shows another three dimensional view of the connector assembly of FIG. 1;

FIG. 3 shows a side view of the connector assembly of FIG. 1;

FIG. 4 shows an exploded three dimensional view of the connector assembly of FIG. 1 connected between the output of a drill motor and a drill pipe of a drilling apparatus;

FIG. 5 shows a sectional side view of the connector assembly of FIG. 1;

FIG. 6 shows a sectional side view of the input connector unit of the connector assembly of FIG. 1;

FIG. 7 shows a sectional side view of the output connector unit of the connector assembly of FIG. 1;

FIG. 8 shows a plan view of the shock assembly unit of FIG. 1, sectioned along section line VIII-VIII of FIG. 3;

FIG. 9 shows another exploded three dimensional view of the connector assembly of FIG. 1, illustrating the manner in which the connector assembly is disassembled for repair purposes;

FIG. 10 shows a three dimensional view of a shock absorption element of the connector assembly of FIG. 1; and

FIG. 11 shows a side view of the shock absorption element of FIG. 10.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the drawings, a connector assembly for use with a drilling apparatus, in accordance with the invention, is designated generally by the reference numeral 10. The connector assembly 10 comprises, broadly, an input connector unit 12, an output connector unit 14 and a number of shock absorption elements 16 mounted between the input and output connector units. The connector assembly defines a longitudinal axis A extending through the input and output shafts.

The input connector unit 12 is connected to the output of a drill motor 18 comprising a hydraulic power head 20, via a power output shaft or quill 22 connected to the power head. The output connector unit 16 is connected to a drill pipe segment 24 which forms part of a string of drill pipe segments including a drilling segment having a drill bit at a lower end thereof and a number of extension segments which are connected in line to one another and to the drilling segment to provide for a hole to be drilled to a required depth. The drill pipe segment 24 is an extension segment which is connected in line with a number of additional extension segments, the number of extension segments varying depending on the depth of the hole to be drilled. The drill motor 18 is thus coupled to the drill pipe segments via the quill and the connector assembly providing for rotation of a string of the drill pipe segments, in use.

The input connector unit 12 includes a top carrier plate 26 and an input shaft 28 having an open upper end 30 defining a screw threaded connector formation 32 which permits the upper end of the input shaft to be screwed into a similarly threaded socket of the output shaft 22 of the drill motor 18. The top carrier plate defines a central aperture within which the input shaft is received. More specifically, the top carrier plate is releasably mounted to the input shaft.

The input shaft 12 has an open lower end 34 and an internal passage 36 which extends between the lower and upper ends. A lower end region 38 of the input shaft projects downwardly beyond an underside 40 of the top carrier plate. The bottom carrier plate defines a central aperture within which the output shaft is received. More specifically, the bottom carrier plate is releasably mounted to the output shaft.

The output connector unit 14 includes a bottom carrier plate 31 and an output shaft 42 having an open lower end 44 and an open upper end 46. The lower end defines an internally screw threaded connector formation 48 which permits the lower end of the output shaft to be screwed onto a similarly threaded formation of the drill pipe extension segment 24. The output shaft defines an internal passage 50 which extends between the upper and lower ends. An upper end region 52 of the output shaft extends upwardly beyond an upper side 54 of the bottom carrier plate.

The connector assembly includes a resiliently deformable rubber sealing member 56 which is located between the lower end 34 of the input shaft 28 and the upper end 46 of the output shaft 42. The lower and upper ends of the input and output shafts, respectively, define seat formations 58 within which the sealing member 56 is seated. The sealing member has an annular configuration and defines a central passage which is aligned with the internal passages 36 and 50 of the input and output shafts, respectively, so as to form a sealed common internal passage for compressed air, extending through the connector assembly.

The shock absorption elements 16 are arranged adjacent one another between the top and bottom carrier plates. Each shock absorption element 16 comprises a shock absorption body having a central core of resiliently deformable shock absorption material such as rubber, a rigid steel upper plate 60 and a rigid steel lower plate 62 located at upper and lower ends, respectively, of the central core. Four upper locating pins 64 extend upwardly from an upper side of the upper rigid plate and four lower locating pins 64 extend downwardly from a lower side of the lower rigid plate. More specifically, each of the upper and lower locating pins are spaced form one another and extend parallel to the longitudinal axis A of the connector assembly. The top and bottom carrier plates define locating holes within which the upper and lower locating pins, respectively, are slidable received. The upper and lower locating pins have castle nuts 66 and hitch pin clips 68 secured thereto at free ends thereof at external sides of the top and bottom carrier plates, which resist separation of the top and bottom carrier plates beyond a predetermined separation spacing limit. The rubber sealing member 56 also provides for a degree of shock absorption of axial and rotational shock forces transmitted between the drill motor and the drill string.

The connector assembly includes four elongate link elements 70 which extend between the top and bottom carrier plates. More specifically, the link elements are mounted to mounting assemblies 72 located near peripheral edges of the top and bottom plates for preventing separation of the top and bottom carrier plates beyond a predetermined separation spacing limit. The mounting assemblies include mounting brackets which define holes in which mounting pins are received and which pass through apertures defined therefor in the link elements; and castle nuts and hitch pin clips for securing the mounting pins to the link elements.

The connector assembly 10 can be dis-assembled relatively easily by removing the bolts 39 and separating the input and output connector units from the shock assembly unit. In order to dis-assemble the connector assembly, the connector assembly is compressed by displacing top and bottom carrier plates towards one another. The hitch pin clips 68 and the castle nuts 66 are removed and the mounting assemblies 72 for the link elements 70 are dis-assembled allowing the removal of the link elements 70. The compression of the connector assembly is thereafter released and the sealing member 56 is removed together with the shock absorption elements 16. Damaged and worn components of the connector assembly can be repaired or replaced relatively easy on site. After repair or replacement of the damaged or worn components the connector assembly is again assembled by following a reverse procedure to that for dis-assembly.

The shock absorption elements provide for absorption and attenuation of axial shocks transmitted between the drill pipe and the drill motor, the link elements defining slots 75 which permit a degree of axial movement of the top and bottom carrier plates while the locating pins 64 slide within the holes defined therefor in the top and bottom carrier plates so as to permit relative axial movement of the top and bottom carrier plates. Due to the resilient deformity of the shock absorption elements, a degree of torsion attenuation is also provided by the shock absorption elements such that the connector assembly provides for absorption of both axial and rotational shock forces transmitted between the drill motor and the drill pipe. Due to the modular design of the connector assembly, if one or more of the input connector unit, the output connector unit and the shock assembly of the connector assembly is damaged, the damaged unti can be removed and replaced on site thereby minimising downtime of the drilling apparatus. As such, the damaged unit only, needs to be repaired and if irreparable, replaced without repairing or replacing the entire connector assembly. 

1. A connector assembly for use with a drilling apparatus, the connector assembly comprising: an input connector unit including a top carrier plate and an input shaft which is connected to the top carrier plate, the input shaft having an open upper end and an open lower end and an internal passage extending between the upper and lower ends, the upper end having a connector formation which is connectable to a power output of a drill motor of the drilling apparatus; an output connector unit including a bottom carrier plate and an output shaft which is connected to the bottom carrier plate, the output shaft having an open upper end and an open lower end and an internal passage extending between the upper and lower ends, the lower end having a connector formation which is connectable to a drill pipe segment of a drill pipe; at least one resiliently deformable shock absorption element which is mounted between the top and bottom carrier plates so as to absorb axial shocks transmitted between the drill motor and the drill pipe; and the input and output shafts defining a common longitudinal axis, with the internal passages of the input and output shafts being in flow communication with one another and an internal passage of the drill pipe.
 2. The connector assembly as claimed in claim 1, wherein the top carrier plate defines a central aperture within which the input shaft is received.
 3. The connector assembly as claimed in claim 1, wherein the bottom carrier plate defines a central aperture within which the output shaft is received.
 4. The connector assembly as claimed in claim 1, wherein a lower end region of the input shaft of the input connector unit projects beyond an underside of the top carrier plate.
 5. The connector assembly as claimed in claim 4, wherein an upper end region of the output shaft of the output connector unit projects beyond an upper side of the bottom carrier plate.
 6. The connector assembly as claimed in claim 5, further comprising a sealing member located between the lower end of the input shaft and the upper end of the output shaft, the sealing member defining a central passage which is aligned with the internal passages of the input and output shaft thereby to form a sealed common central internal passage extending through the connector assembly.
 7. The connector assembly as claimed in any one of claim 1, further comprising a number of shock absorption elements which are arranged adjacent one another between the top and bottom carrier plates.
 8. The connector assembly as claimed in claim 7, wherein each shock absorption element comprises a shock absorption body having a central core member of a resiliently deformable shock absorption material, an upper rigid plate and a lower rigid plate fixedly located at upper and lower ends, respectively, of the core member.
 9. The connector assembly as claimed in claim 8, wherein each shock absorption element includes at least two upper locating pins which extend upwardly from an upper side of the upper rigid plate and at least two lower locating pins which extend downwardly from a lower side of the lower rigid plate, the locating pins extending parallel to the longitudinal axis of the connector assembly.
 10. The connector assembly as claimed in claim 8, wherein the central core member of each shock absorption element is of rubber, while the upper and lower rigid plates of each shock absorption element are of steel.
 11. The connector assembly as claimed in claim 9, wherein the top and bottom carrier plates define locating holes within which the upper and lower locating pins, respectively, are slidably received.
 12. The connector assembly as claimed in claim 11, wherein the upper and lower locating pins have stop elements near free ends thereof at external sides of the top and bottom carrier plates, the stop elements resisting separation of the top and bottom carrier plates beyond a predetermined separation spacing limit.
 13. The connector assembly as claimed in claim 12, further comprising a number of elongate link elements which extend between and which are connected near opposite ends thereof to the top and bottom carrier plates, respectively.
 14. The connector assembly as claimed in claim 13, wherein the top and bottom carrier plates have mounting formations for mounting the link elements, disposed near peripheral edges of the carrier plates, the link elements extending between aligned mounting formations of the top and bottom carrier plates, respectively. 